If I submit my PR visa application and then a few months down the line I secure a job. Do I need to tell the Canadian High Commission straight away? Or can I apply for work permit after a job has been offered?

In the userguide for simplified application process is mentions:
"Important: If you personal situation changes while your application is being processed, do not contact the visa office. An update of your situation will automatically be asked before the visa office is ready to access your application. We will not consider any information request."

To me this means that if I head over to Canada on a work permit I don't need to inform them of my situation until they request it. Of course I still need to inform them of a change of address.

Language Tests - I have been to the York Emigration fare in 2004 and 2005 and also this year. The Canada Immigration where at the 2004 and 2005 event and on both they mentioned that if you have a british passport and were born in the UK. Then you would automatically get full points for English as your main language. Would you agree to this or is it recommended to do the language test?